Mating connectors are commonly used to form a separable connection between two flexible electric wires each comprised of a conductive center core and an insulating overwrap. A typical connector includes an exterior nonconductive or insulating housing, and an electrically conductive terminal mounted within the housing. The housings cooperate in typical telescoped fit with one another and wiping or contact areas of the respective terminals engage to establish an electrical connection across the terminals. Each housing further has an opening into which the electric wire fits for making electrical connection with the terminal. Strain relief means must be provided to secure the wire mechanically either to the terminal and/or to the housing.
In some applications, a bank of like electrical male terminals are housed within a common housing and define a connector that completes a plurality of electrical connections with a cooperating connector having a like number of female electrical terminals. Further, with the wide use of low voltage electrical control circuits, the size and current carrying capacity of these connectors have been dramatically reduced. Under such circumstances, it is desirable to minimize the manual labor or assembly steps required in order to connect each wire to a corresponding terminal.
One type of conventional connector requires that the wire be cut to length and its end stripped of installation overwrap to expose the conductive center core which is then brought into contact with the terminal and soldered to the terminal. The terminal is then fitted into the housing and locked in a suitable manner to define the terminated connector assembly. A solderless or insulation displacement type connector shortens the foregoing operation in that the wire need only be cut to length and be forced into the terminal, and special cutting edges formed on the terminal automatically displace or strip a portion of the insulation overwrap to establish electrical contact with the conductive center core.
The same cutting and contact edges frequently serve also as the strain relief means securing the wire and terminal mechanically. Additional tabs may be provided on the terminal to dig into the insulation overwrap of the wire as it is positioned in place against the terminal. However, the retaining capacity is limited by the durability and strength of the terminal and the established frictional gripping of the wire and/or insulation overwrap. Frequently, the mere tensioning or pulling the wire at certain angles relative to the terminal or connector releases the strain relief means to allow the wire to become separated from the connector.
Various patents which illustrate solderless electrical connectors to which the invention pertains include U.S. Pat. No. 3,926,498 issued to Hoppe Jr., U.S. Pat. No. 4,040,702 issued to McKee et al, and U.S. Pat. No. 4,050,760 issued to Cohen.